Add cipher mode and pattern encryption support

[ Merge of http://go/wvgerrit/16364 ]

http://go/wvgerrit/16249 changed the name of the encryption pattern
structure from OEMCrypto_PatternDesc to OEMCrypto_CENCEncryptPatternDesc
to remove ambiguity. These are matching changes to CDM core.

[ Merge of http://go/wvgerrit/16340 ]

This CL passes the cipher mode in the license to OEMCrypto when
keys are loaded and specifies the pattern encryption scheme to
OEMCrypto_DecryptCENC.

b/20630275

Change-Id: I86b82bbdc891fd0100beb9fad385ca2082176271

libwvdrmengine/cdm/core/include/crypto_key.h

@@ -17,6 +17,7 @@ class CryptoKey {
   const std::string& key_data_iv() const { return key_data_iv_; }
   const std::string& key_control() const { return key_control_; }
   const std::string& key_control_iv() const { return key_control_iv_; }
+  CdmCipherMode cipher_mode() const { return cipher_mode_; }
   void set_key_id(const std::string& key_id) { key_id_ = key_id; }
   void set_key_data(const std::string& key_data) { key_data_ = key_data; }
   void set_key_data_iv(const std::string& iv) { key_data_iv_ = iv; }
@@ -24,6 +25,9 @@ class CryptoKey {
   void set_key_control_iv(const std::string& ctl_iv) {
     key_control_iv_ = ctl_iv;
   }
+  void set_cipher_mode(CdmCipherMode cipher_mode) {
+    cipher_mode_ = cipher_mode;
+  }
 
   bool HasKeyControl() const { return key_control_.size() >= 16; }
 
@@ -33,6 +37,7 @@ class CryptoKey {
   std::string key_data_;
   std::string key_control_;
   std::string key_control_iv_;
+  CdmCipherMode cipher_mode_;
 };
 
 }  // namespace wvcdm

libwvdrmengine/cdm/core/include/wv_cdm_types.h

@@ -271,6 +271,26 @@ struct CdmHlsData {
   std::string uri;
 };
 
+enum CdmCipherMode {
+  kCipherModeCtr,
+  kCipherModeCbc,
+};
+
+// For schemes that do not use pattern encryption (cenc and cbc1), encrypt
+// and skip should be set to 0. For those that do (cens and cbcs), it is
+// recommended that encrypt+skip bytes sum to 10 and for cbcs that a 1:9
+// encrypt:skip ratio be used. See ISO/IEC DIS 23001-7, section 10.4.2 for
+// more information.
+struct CdmCencPatternEncryptionDescriptor {
+  size_t encrypt_blocks;  // number of 16 byte blocks to decrypt
+  size_t skip_blocks;     // number of 16 byte blocks to leave in clear
+  size_t offset_blocks;   // offset into the pattern for this call, in blocks
+  CdmCencPatternEncryptionDescriptor()
+      : encrypt_blocks(0),
+        skip_blocks(0),
+        offset_blocks(0) {}
+};
+
 struct CdmDecryptionParameters {
   bool is_encrypted;
   bool is_secure;
@@ -284,6 +304,7 @@ struct CdmDecryptionParameters {
   size_t decrypt_buffer_offset;
   uint8_t subsample_flags;
   bool is_video;
+  CdmCencPatternEncryptionDescriptor pattern_descriptor;
   CdmDecryptionParameters()
       : is_encrypted(true),
         is_secure(true),